When performing operations directed to obtaining hydrocarbons from a subterranean formation it is often desirable to perform an analysis of the subterranean formation. The characteristics of the subterranean formation may be used to ensure efficient and successful operations. One way to characterize the subterranean formation in which the hydrocarbon operations are being performed is to analyze the formation during the drilling operations.
Drilling fluids (also referred to herein as “drilling muds”) are often circulated downhole during drilling operations in a subterranean formation. The drilling fluids perform a number of functions, including lubricating the area being drilled and removing any cuttings that are created during the drilling operations. When the drilling fluids are returned to the surface, they may be directed to a shale shaker. The returned drilling fluids typically includes a mixture of the drilling fluid that was pumped downhole and cutting from the region that is being drilled. This mixture may be directed to a shale shaker. The fluid portion of the mixture may pass through screens in the shale shaker while the cuttings remain on the screen.
Once the fluid portion of the returned mixture is separated from the cuttings, a mud logger may periodically go to the shale shaker and select certain cuttings which he deems are representative of the cuttings that are returned to the surface with the drilling fluid during a particular time period. The selected samples of the cuttings are removed from the screen and the mud logger may then prepare them for further analysis by, for example, washing them. The mud logger may then select one or two of the previously selected cutting samples to analyze as a way to determine the mineralogy of the formation being drilled. This small group of samples may then be smashed into a powder which can be analyzed using LASER spectroscopy or other methods to determine the elemental composition of the samples in order to infer the formation mineralogy.
The current methods of analyzing the mineralogy of the formation based on the cuttings that are returned to the surface with the drilling fluids has several disadvantages. First, the current methods do not provide a continuous analysis of the cuttings that are returned to the surface due to the time lag between the time the different samples are taken by the mud logger. Moreover, the current methods are inherently subject to human error and inaccuracies since the mud logger selects the samples that he deems are representative of the cuttings being returned to the surface during a given time period. Further, the current methods are labor intensive as they require personnel to manually select and process sample cuttings and analyze them to determine the formation mineralogy. Additionally, because a limited number of samples are taken at a given time, the operator cannot obtain a wide area view of the mineralogy and/or lithology of the cuttings.
While embodiments of this disclosure have been depicted and described and are defined by reference to example embodiments of the disclosure, such references do not imply a limitation on the disclosure, and no such limitation is to be inferred. The subject matter disclosed is capable of considerable modification, alteration, and equivalents in form and function, as will occur to those skilled in the pertinent art and having the benefit of this disclosure. The depicted and described embodiments of this disclosure are examples only, and not exhaustive of the scope of the disclosure.